The invention relates to prior art such as is known, e.g., from CH Patent Application No. 4135/83-3 of 7/28/1983.
In the case of arc furnaces and pot furnaces, the bottom and bath electrode, respectively, is exposed to a constant very high thermal stress and is cooled mainly by a liquid cooling. Especially in the melt-down phase in arc furnaces or in the heat-up phase in pot furnaces, the resulting heat loss results in a relatively large thermal flow in the bottom or bath electrode, respectively, in the direction of the furnace vessel or pot bottom, respectively. The varying thermal flow in the bottom or bath electrode, respectively, means, with constant length of the bottom or bath electrode, a varying temperature difference between its cooled zone and the zone in contact with the melt. But with still greater heat supply, no higher temperature difference is present, since the electrode cannot be hotter on the inside than the melting temperature. In other words, more heat can be conveyed only if the electrode becomes shorter--i.e., melts. With insufficient cooling or stopping of the cooling, the operating reliability of the furnace operation is no longer fully guaranteed, since the electrode, in this case, could melt to the extent that there is the danger of a melting breakthrough. With arc furnaces a forced cooling (e.g., a liquid cooling of the bottom electrode, since the furnace is stationary) can be continuously maintained.
However, in the case of pot furnaces, cooling of the bath electrode is more problematical because of the nonstationary operating condition. In the melt heat-up station at the continuous casting machine, in the metallurgical treatment station possibly present, and at the melting furnace, the pot can be constantly connected to forced external cooling from the outside. During transport of the pot to the individual places mentioned above (which are often geographically far from one another), cooling of the bath electrode is costly, since, e.g., the hoses for feeding and removal of the coolant necessary for the cooling must constantly be carried with the pot.